Vibration-damping device

ABSTRACT

The present invention relates to a vibration-damping device ( 10 ) which is provided with: a tubular first attachment member ( 11 ) joined to one of a vibration generating unit and a vibration receiving unit; a second attachment member ( 12 ) joined to the other thereof; an elastic body ( 13 ) which joins the first attachment member ( 11 ) to the second attachment member ( 12 ); and a partition member ( 16 ) which partitions a liquid chamber in the first attachment member ( 11 ) into a first liquid chamber ( 14 ) and a second liquid chamber ( 15 ), and in which at least one of the first liquid chamber ( 14 ) and the second liquid chamber ( 15 ) has the elastic body ( 13 ) as a portion of a wall surface thereof. A vortex chamber unit ( 30 ) through which the first liquid chamber ( 14 ) communicates with the second liquid chamber ( 15 ) is formed in the partition member ( 16 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2015/060463 filed Apr. 2, 2015, claiming priority based onJapanese Patent Application No. 2014-079418 filed Apr. 8, 2014, thecontents of all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a vibration-damping device which isapplied to, for example, vehicles, industrial machines, and so on andwhich absorbs and attenuates vibrations of vibration generating unitssuch as engines.

Priority is claimed on Japanese Patent Application No. 2014-079418,filed Apr. 8, 2014, the content of which is incorporated herein byreference.

BACKGROUND ART

A constitution disclosed in, for example, Patent Document 1 is known assuch a type of vibration-damping device. Such a vibration-damping deviceincludes a tubular first attachment member joined to one of a vibrationgenerating unit and a vibration receiving unit, a second attachmentmember joined to the other of the vibration generating unit and thevibration receiving unit, an elastic body which joins the firstattachment member to the second attachment member, and a partitionmember which partitions a liquid chamber in the first attachment memberin which a liquid is sealed into a first liquid chamber and a secondliquid chamber. The vibration-damping device further includes a firstrestriction passage and a second restriction passage through which thefirst and second liquid chambers communicate with each other, a cylinderchamber which is provided between the first liquid chamber and thesecond liquid chamber, and a plunger member which is arranged movablybetween an open position and a closed position in the cylinder chamber.

A plurality of types of vibrations with different frequencies such as,for example, idle vibrations and shake vibrations are input to thevibration-damping device. For this reason, resonance frequencies of thefirst restriction passage and the second restriction passage are set(tuned) to frequencies of the different types of vibrations in thevibration-damping device. The plunger member is moved between the openposition and the closed position in accordance with frequencies of theinput vibrations so that a restriction passage through which the liquidflows is switched between the first restriction passage and the secondrestriction passage.

CITATION LIST Patent Document

[Patent Document 1]

Japanese Unexamined Patent Application, First Publication No.2007-120598

SUMMARY OF INVENTION Technical Problem

However, there is room for improve terms of simplification of astructure and facilitation of manufacture in the conventionalvibration-damping device.

Also, in the conventional vibration-damping device, when unintentionalvibrations such as, for example, minute vibrations which are higher infrequency and remarkably smaller in amplitude than a resonance frequencyof the restriction passage determined by a path length, across-sectional area, and so on of the restriction passage are input,the dynamic spring constant increases due to clogging of the restrictionpassage or the like. As a result, this may affect product features ofthe vibration-damping device such as ride comfort of vehicles.

The present invention was made in view of the above-describedcircumstances, and an object of the present invention is to provide avibration-damping device in which simplification of a structure andfacilitation of manufacture can be achieved while product features aresecured.

Solution to Problem

In order to accomplish the object, the present invention suggests thefollowing means.

A first aspect related to the present invention is a vibration-dampingdevice in which at least one of a first liquid chamber and a secondliquid chamber has an elastic body as a portion of a wall surfacethereof, in which the vibration-damping device includes: a tubular firstattachment member joined to one of a vibration generating unit and avibration receiving unit; a second attachment member joined to the otherof the vibration generating unit and the vibration receiving unit; anelastic body which joins the first attachment member to the secondattachment member; and a partition member which partitions a liquidchamber in the first attachment member in which a liquid is sealed intothe first liquid chamber and the second liquid chamber. In thevibration-damping device, the partition member is formed with a vortexchamber unit through which the first liquid chamber communicates withthe second liquid chamber. The vortex chamber unit is provided with anannular vortex chamber, a first communicating section through which thevortex chamber communicates with the first liquid chamber, and a secondcommunicating section through which the vortex chamber communicates withthe second liquid chamber. At least one of the first communicatingsection and the second communicating section includes a rectifyingpassage which extends outward in the radial direction from a portion ofthe partition member which is more inward in a radial direction of thevortex chamber than the vortex chamber and are open at an innercircumferential surface of the vortex chamber which faces the outside inthe radial direction in a circumferential direction of the vortexchamber. The vortex chamber is formed to rotate a liquid flowing intothe vortex chamber from the rectifying passage in accordance with a flowvelocity thereof.

In this case, when vibrations are input, and a liquid flows through thevortex chamber between the first liquid chamber and the second liquidchamber, if a flow velocity of the liquid flowing into the vortexchamber from the rectifying passage is sufficiently high, a swirl flowof the liquid is formed in the vortex chamber. Thus, pressure loss ofthe liquid is increased due to, for example, energy toss occurring whenthe swirl flow is formed, energy loss due to friction between the liquidand wall surfaces of the vortex chamber, and so on, and the vibrationsare thus absorbed and attenuated. On the other hand, if the flowvelocity of the liquid flowing into the vortex chamber from therectifying passage is low, the rotation of the liquid in the vortexchamber is suppressed. Thus, an increase in a dynamic spring constant issuppressed due to the liquid which smoothly passes through the vortexchamber.

According to the vibration-damping device, the swirl flow of the liquidis formed in the vortex chamber so that the pressure loss of the liquidis increased, and the vibrations can thus be absorbed and attenuated.For example, when normal vibrations such as idle vibrations and shakevibrations are input, the vibrations can be absorbed and attenuated inaccordance with the flow velocity of the liquid irrespective of thefrequencies of the vibrations. Also, since the rectifying passage isopen at the inner circumferential surface of the vortex chamber in thecircumferential direction of the vortex chamber, a size of the swirlflow is secured by increasing an outer diameter of the vortex chamber,and the pressure loss of the liquid can thus be reliably increased. Inaddition, the rectifying passage is disposed inside the vortex chamberin the radial direction so that the compactness of the vibration-dampingdevice can be realized. Therefore, simplification of a structure andfacilitation of manufacture can be achieved while a plurality of kindsof vibrations having different frequencies are absorbed and attenuated.

Also, since an increase in a dynamic spring constant is suppressed in astate in which the flow velocity is low and the rotation of the liquidin the vortex chamber is suppressed, when the flow velocity of theliquid is lower than that when normal vibrations are input, such as whenunintentional vibrations such as, for example, minute vibrations higherin frequency and remarkably lower in amplitude than the normalvibrations are input, the increase in the dynamic spring constant can besuppressed. Thus, product features of the vibration-damping device canbe easily secured.

In a second aspect of the present invention, in the vibration-dampingdevice of the first aspect, the rectifying passage is included in bothof the first communicating section and the second communicating section.

In this case, since the rectifying passages are included in both of thefirst communicating section and the second communicating section, theliquid which flows into the second liquid chamber from the first liquidchamber is caused to flow into the vortex chamber via the firstrectifying passage serving as the rectifying passage included in thefirst communicating section so that the pressure loss can be increased,and the liquid which flows into the first liquid chamber from the secondliquid chamber is also caused to flow into the vortex chamber via thesecond rectifying passage serving as the rectifying passage included inthe second communicating section so that the pressure loss of the liquidcan be increased. Thus, the vibrations can be effectively absorbed andattenuated.

In a third aspect of the present invention, in the vibration-dampingdevice of the second aspect, a first rectifying passage included in thefirst communicating section as the rectifying passage and a secondrectifying passage included in the second communicating section as therectifying passage extend outward in the radial direction and graduallyextend in common in one direction in the circumferential direction.

In this case, after the liquid flowing into the vortex chamber from thefirst communicating section via the first rectifying passage rotates inthe vortex chamber in the one direction in the circumferentialdirection, the liquid is caused to flow into the second communicatingsection via the second rectifying passage. At this time, since thesecond rectifying passages extend outward in the radial direction incommon with the first rectifying passages and extend in one direction inthe circumferential direction, a direction in which the liquid rotatesin the vortex chamber in the circumferential direction and a directionin which the second rectifying passages extend in the circumferentialdirection can be commonly set to be the one direction in thecircumferential direction. Thus, it is difficult for the liquid whichrotates in the vortex chamber to flow into the second rectifyingpassages, and thus the liquid can efficiently rotate in the vortexchamber, in other words, a sufficient distance to move the liquid can besecured, and the pressure loss of the liquid can thus be more reliablyincreased.

Also, after the liquid flowing into the vortex chamber from the secondcommunicating section via the second rectifying passage rotates in thevortex chamber in the one direction in the circumferential direction,the liquid is caused to flow into the first communicating section viathe first rectifying passage. At this time, since the first rectifyingpassages extend outward in the vortex chamber radial direction in commonwith the second rectifying passages and extend in the one direction inthe circumferential direction, the direction in which the liquid rotatesin the vortex chamber in the circumferential direction and a directionin which the first rectifying passages extend in the circumferentialdirection can be commonly set to be the one direction in thecircumferential direction. Thus, it is difficult for the liquid whichrotates in the vortex chamber to flow into the first rectifyingpassages, and thus the liquid can efficiently rotate in the vortexchamber. In other words, a sufficient distance to move the liquid can besecured, and the pressure loss of the liquid can thus be more reliablyincreased.

In the fourth aspect related to the present invention, in thevibration-damping device according to any one of the first to thirdaspects, a communicating section of the first communicating section andthe second communicating section which is included in the rectifyingpassage is provided with a relay chamber of the partition member whichis more inward in the radial direction than the vortex chamber. Therelay chamber communicates with the first liquid chamber or the secondliquid chamber via an opening which is open in an axial direction of thevortex chamber, and the rectifying passage extends outward in the radialdirection from an inner circumferential surface of the relay chamberwhich faces the inside in the radial direction and is open at the innercircumferential surface of the vortex chamber.

In this case, since the rectifying passage extends outward in the radialdirection from the inner circumferential surface of the relay chamberand is open at the inner circumferential surface of the vortex chamber,after the liquid which flows into the relay chamber from the firstliquid chamber or the second liquid chamber in the axial direction iscaused to flow through the rectifying passage in the radial direction,the liquid can be caused to flow into the vortex chamber from the innercircumferential surface of the vortex chamber in the circumferentialdirection. Thus, the liquid flowing into the vortex chamber from therectifying passage can be easily accurately caused to rotate inaccordance with the flow velocity thereof.

Advantageous Effects of Invention

According to the present invention, simplification of a structure andfacilitation of manufacture can be achieved while product features aresecured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of a vibration-dampingdevice related to an embodiment of the present invention.

FIG. 2 is a plan view showing a partition member constituting thevibration-damping device shown in FIG. 1.

FIG. 3 is a lateral cross-sectional view showing a major part of thepartition member shown in FIG. 2.

FIG. 4 is a longitudinal cross-sectional view showing a state in whichthe major part including a core section is exposed in the partitionmember shown in FIG. 2.

FIG. 5 is a lateral cross-sectional view showing a major part of apartition member constituting a vibration-damping device related to afirst modified embodiment of the present invention.

FIG. 6 is a lateral cross-sectional view showing a major part of apartition member constituting a vibration-damping device related to asecond modified embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a vibration-damping device related to thepresent invention will be described with reference to FIGS. 1 to 4.

As shown in FIG. 1, a vibration-damping device 10 is provided with atubular first attachment member 11 joined to one of a vibrationgenerating unit and a vibration receiving unit, a second attachmentmember 12 joined to the other of the vibration generating unit and thevibration receiving unit, an elastic body 13 which joins the firstattachment member 11 to the second attachment member 12, and a partitionmember 16 which partitions a liquid chamber in the first attachmentmember 11 in which a liquid L is sealed into a main liquid chamber (afirst liquid chamber) 14 having the elastic body 13 as a portion of awall surface thereof and a subsidiary liquid chamber (a second liquidchamber) 15.

In the illustrated example, the second attachment member 12 is formed ina columnar shape, the elastic body 13 is formed in a tubular shape, andthe first attachment member 11, the second attachment member 12, and theelastic body 13 are disposed coaxially with a common axis. Hereinafter,the common axis is referred to as an axis O (an axis of the firstattachment member), the main liquid chamber 14 side in an axial Odirection (an axial direction of a vortex chamber) is referred to as oneside, the subsidiary liquid chamber 15 side is referred to as the otherside, a direction perpendicular to the axis O is referred to as a radialdirection, and a direction around the axis O is referred to as acircumferential direction.

When the vibration-damping device 10 is mounted in, for example, avehicle the second attachment member 12 is joined to an engine servingas a vibration generating unit, and the first attachment member 11 isjoined to a vehicle body serving as a vibration receiving unit via abracket (not shown), thereby suppressing vibrations of the engine frombeing transferred to the vehicle body. The vibration-damping device 10is a liquid sealed type in which the liquid L such as, for example,ethylene glycol water, or silicone oil, is sealed in the liquid chamberof the first attachment member 11.

The first attachment member 11 is provided with a one-side outer rimbody 21 on the one side in the axial O direction and an other-side outerrim body 22 on the other side.

The elastic body 13 is joined to an end of the one-side outer rim body21 on the one side in a liquid-tight state, and an opening of theone-side outer rim 21 of the one side is closed by the elastic body 13.An end 21 a of the one-side outer rim body 21 on the other side isformed larger in diameter than other portions. Also, an inside of theone-side outer rim body 21 is the main liquid chamber 14. A liquidpressure of the main liquid chamber 14 changes as the elastic body 13 isdeformed when vibrations are input and an inner capacity of the mainliquid chamber 14 is thus changed.

An annular groove 21 b of the one-side outer rim body 21 whichcontinuously extends throughout the entire circumference thereof aboutthe axis O is formed in a portion connected from the other side to aportion of the one-side outer rim body 21 to which the elastic body 13is joined.

A diaphragm 17 is joined to an end of the other-side outer rim body 22on the other side in a liquid-tight state, and an opening of theother-side outer rim body 22 on the other side is closed by thediaphragm 17. An end 22 a of the other-side outer rim body 22 on the oneside is formed larger in diameter than other portions and is fitted intothe end 21 a of the one-side outer rim body 21 on the other side. Thepartition member 16 is fitted into the other-side outer rim body 22. Aportion inside the other-side outer rim body 22 which is between thepartition member 16 and the diaphragm 17 is the subsidiary liquidchamber 15. The subsidiary liquid chamber 15 has the diaphragm 17 as aportion of a wall surface and is expanded or contracted as the diaphragm17 is deformed. The other-side outer rim body 22 is covered with arubber membrane integrally formed with the diaphragm 17 overapproximately the entire area.

A female threaded part 12 a is formed on an end surface of the secondattachment member 12 of the one side coaxially with the axis O. Thesecond attachment member 12 protrudes from the first attachment member11 toward the one side. A flange part 12 b which protrudes outward in aradial direction and continuously extends throughout the entirecircumference of the second attachment member 12 about the axis O isformed on the second attachment member 12. The flange part 12 b isspaced apart from an edge of the first attachment member 11 on the oneside, toward the one side.

The elastic body 13 is formed by an elastic member such as, for example,a rubber material and is formed in a tubular shape whose diameter isgradually increased from the one side to the other side. An end of theelastic body 13 on the one side is joined to the second attachmentmember 12, and an end thereof on the other side is joined to the firstattachment member 11.

An inner circumferential surface of the one-side outer rim body 21 ofthe first attachment member 11 is covered with a rubber membraneintegrally formed with the elastic body 13 over approximately the entirearea.

The partition member 16 is formed in a discoid shape which is disposedcoaxially with the axis O and is fitted into the first attachment member11. The partition member 16 is provided with a flange part 16 a whichprotrudes outward in a radial direction. The flange part 16 a isprovided at an end of the partition member 16 on the one side. Theflange part 16 a is disposed in the end 22 a of the other-side outer rimbody 22 on the one side.

Vortex chamber units 30 through which the main liquid chamber 14communicates with the subsidiary liquid chamber 15 are formed in thepartition member 16, and the main liquid chamber 14 and the subsidiaryliquid chamber 15 communicate with each other only via the vortexchamber units 30.

The plurality of vortex chamber units 30 are provided in the partitionmember 16. The plurality of vortex chamber units 30 are formed in thesame shape and size. One vortex chamber unit 30 among the plurality ofvortex chamber units 30 is disposed coaxially with the axis O and theremainder of the plurality of vortex chamber units 30 are disposed inthe circumferential direction to surround the vortex chamber unit 30disposed coaxially with the axis O from an outside in the radialdirection.

Each of the vortex chamber units 30 is provided with an annular vortexchamber 31, a first communicating section 32 through which the vortexchamber 31 communicates with the main liquid chamber 4, and a secondcommunicating section 33 through which the vortex chamber 31communicates with the subsidiary liquid chamber 15.

A vortex chamber axis M serving as an axis of the vortex chamber 31extends in parallel with the axis O in the axial O direction.

As shown FIGS. 2 to 4, the first communicating section 32 is providedwith a first relay chamber 32 a, and the second communicating section 33is provided with a second relay chamber 33 a.

The first relay chamber 32 a and the second relay chamber 33 a aredisposed more inward in a radial direction of the vortex chamber 31(hereinafter referred to as a vortex chamber radial direction) than thevortex chamber 31 and disposed coaxially with the vortex chamber axis M.Inner circumferential surfaces of the first relay chamber 32 a and thesecond relay chamber 33 a (an inner circumferential surface of a corepart 39 d to be described below which forms the first relay chamber 32 aand the second relay chamber 33 a) are formed in circular shapes aboutthe vortex chamber axis M. The first relay chamber 32 a communicateswith one of the main liquid chamber 14 and the subsidiary liquid chamber15 via an opening which is open in the axial O direction, and the secondrelay chamber 33 a communicates with the other of the main liquidchamber 14 and the subsidiary liquid chamber 15 via an opening which isopen in the axial O direction. In this embodiment, the first relaychamber 32 a communicates with the main liquid chamber 14 via an openingwhich is open in the axial O direction, and the second relay chamber 33a communicates with the subsidiary liquid chamber 15 via an openingwhich is open in the axial O direction. The first relay chamber 32 a andthe second relay chamber 33 a are formed to be symmetrical to each otherin the axial O direction.

As shown in FIGS. 2 to 4 the first communicating section 32 is providedwith first rectifying passages 32 b, and the second communicatingsection 33 is provided with second rectifying passages 33 b (here, atleast one of the first rectifying passages 32 b and the secondrectifying passages 33 b may be provided). The first rectifying passages32 b and the second rectifying passages 33 b extend outward in thevortex chamber radial direction from a portion of the partition member16, which is more inward in the vortex chamber radial direction than thevortex chamber 31, and are open at an inner circumferential surface (anouter circumferential surface of the core part 39 d to be describedbelow which forms the vortex chamber 31) of the vortex chamber 31, whichfaces the outside in the vortex chamber radial direction, in a directionaround the vortex chamber axis M serving as a circumferential directionof the vortex chamber 31 (hereinafter referred to as a vortex chambercircumferential direction). In this embodiment, the first rectifyingpassages 32 b and the second rectifying passages 33 b extend outward inthe vortex chamber radial direction from the inner circumferentialsurface of the first relay chamber 32 a and the second relay chamber 33a which faces the inside in the vortex chamber radial direction (theinner circumferential surface of the core part 39 d to be describedbelow which form the first relay chamber 32 a and the second relaychamber 33 a) and are open at the inner circumferential surface of thevortex chamber 31 which faces the outside in the vortex chamber radialdirection.

The first rectifying passages 32 b are in communication with the firstrelay chamber 32 a and the vortex chamber 31. A pair of first rectifyingpassages 32 b are point-symmetrically disposed with respect to thevortex chamber axis M to surround the first relay chamber 32 a in aplanar view of the vortex a chamber 31 viewed from the axial Odirection. The pair of first rectifying passages 32 b extend from afirst relay chamber 32 a in a direction along an orthogonal planeperpendicular to the axis O.

The second rectifying passages 33 b are in communication with the secondrelay chamber 33 a and the vortex chamber 31. In the planar view, a pairof second rectifying passages 33 b are point-symmetrically disposed withrespect to the vortex chamber axis M to surround the second relaychamber 33 a. The pair of second rectifying passages 33 b extend fromthe second relay chamber 33 a in the direction along the orthogonalplane.

The first rectifying passages 32 b and the second rectifying passages 33b extend outward in the vortex chamber radial direction and graduallyextend in common in one direction in the vortex chamber circumferentialdirection. The first rectifying passages 32 b and the second rectifyingpassages 33 b are formed in the same shape and size and are disposed tooverlap each other in the planar view. The first rectifying passages 32b and the second rectifying passages 33 b are gradually reduced in widthfrom the inside to the outside in the vortex chamber radial direction inthe planar view. Lateral surfaces of the first rectifying passages 32 band the second rectifying passages 33 b which face the vortex chamberaxis M are formed as convex curved surfaces which are convex in theother direction of the vortex chamber circumferential direction in theplanar view.

In this embodiment, the vortex chamber 31 is formed to rotate a liquid Lflow into the vortex chamber 31 from the first rectifying passages 32 band the second rectifying passages 33 b in accordance with a flowvelocity of the liquid L. The liquid L flowing into the vortex chamber31 from the first rectifying passages 32 b and the second rectifyingpassages 33 b rotates to flow along the inner circumferential surface ofthe vortex chamber 31 which faces the outside in the vortex chamberradial direction.

As shown in FIG. 1, the partition member 16 is formed by three dividingbodies 39 and 40 including a central dividing body 39 and a pair ofouter dividing bodies 40. The partition member 16 is formed such thatthe pair of outer dividing bodies 40 surround the central dividing body39 in the axial O direction, and for example, the three dividing bodies39 and 40 are fixed by fixing means (not shown) such as bolts in theaxial O direction.

The central dividing body 39 includes a plate-shaped main body 39 awhich aces in the axial O direction. The main body 39 a is disposedcoaxially with the axis O. The main body 39 a is formed with a pluralityof through holes 39 c constituting the vortex chambers 31. A tubularcore part 39 d extending in the axial O direction is disposed in each ofthe through holes 39 c. A central portion of an outer circumferentialsurface of the core part 39 d in the axial O direction is joined to themain body 39 a via bridge sections 39 e. A pair of bridge sections 39 eare disposed to surround the core part 39 d in the vortex chamber radialdirection. The bridge sections 39 e are disposed to be shifted in thevortex chamber circumferential direction with respect to outer openingsof the first rectifying passages 32 b and the second rectifying passages33 b in the vortex chamber radial direction. The pair of bridge sections39 e divide a communicating gap between the outer circumferentialsurface of the core part 39 d and an inner circumferential surface ofthe through hole 39 c into two gaps in the vortex chambercircumferential direction.

A partition plate 39 f is disposed inside the core part 39 d. Front andrear surfaces of the partition plate 39 f face in the axial O direction,and an outer circumferential edge portion of the partition plate 39 f isjoined to the central portion of the inner circumferential surface ofthe core part 39 d in the axial O direction. The partition plate 39 fdivides an inside of the core part 39 d in the axial O direction, aportion in the core part 39 d which is closer to the one side than thepartition plate 39 f is formed with the first relay chamber 32 a, and aportion therein which is closer to the other side than the partitionplate 39 f is formed with the second relay chamber 33 a. Portions of thecore part 39 d which are closer to the one side than the partition plate39 f are formed with the first rectifying passages 32 b, and portionsthereof which are closer to the other side than the partition plate 39 fare formed with the second rectifying passages 33 b.

The pair of outer dividing bodies 40 are formed in the same shape andsize. The outer dividing bodies 40 are formed in a plate shape facing inthe axial O direction and are disposed coaxially with the axis O. Theouter dividing bodies 40 on the one side in the axial O direction arerecessed toward the one side in the axial O direction and are providedwith concave portions 40 a which are open toward the other side in theaxial O direction, and the outer dividing bodies 40 on the other side inthe axial O direction are recessed toward the other side in the axial Odirection and are provided with concave portions 40 a which are opentoward the one side in the axial O direction.

The core part 39 d is accommodated in each of the concave portions 40 a.A bottom surface of the concave portion 40 a is in contact with an endsurface of the core part 39 d which faces in the axial O direction in aliquid-tight state. Through holes which have the same diameter as thefirst relay chamber 32 a and the second relay chamber 33 a pass throughthe bottom surface of the concave portion 40 a in the axial O direction.

An inner circumferential surface of the concave portion 40 a isoutwardly spaced apart from the outer circumferential surface of thecore part 39 d in the vortex chamber radial direction. Thus, annulargaps which extend throughout the entire circumference in the vortexchamber circumferential direction are provided between the innercircumferential surface of the concave portions 40 a and the outercircumferential surface of the core part 39 d. In other words, a pair ofannular gaps are provided to surround the central dividing body 39 inthe axial O direction and communicate with each other via thecommunicating gap. The annular gaps and the communicating gap constitutethe vortex chamber 31. The vortex chamber 31 has a circular innercircumferential surface.

An action of the vibration-damping device 10 constituted as describedabove will be described.

When vibrations in the axial O direction are input from the vibrationgenerating unit to the vibration-damping device 10 as shown in FIG. 1,the first attachment member 11 and the second attachment member 12 arerelatively displaced while elastically deforming the elastic body 13 sothat a liquid pressure of the main liquid chamber 14 changes. Thus, theliquid L is caused to reciprocate between the main liquid chamber 14 andthe subsidiary liquid chamber 15 via the vortex chamber units 30.

At this time, the liquid L in the main liquid chamber 14 is caused toflow toward the subsidiary liquid chamber 15 via the vortex chamberunits 30. Thus, the liquid L flows into the vortex chamber 31 via thefirst relay chamber 32 a and the first rectifying passages 32 b. At thistime, the liquid L passes through the first rectifying passages 32 b sothat a flow velocity of the liquid L can be increased.

Here, vibrations such as, for example, idle vibrations (for example,whose frequencies are 18 Hz to 30 Hz and whose amplitudes are ±0.5 mm orless) and shake vibrations (for example, whose frequencies are 14 Hz orless and whose amplitudes are greater than ±10.5 mm) lower in frequencyand larger in amplitude than the idle vibrations are nor al input to thevibration-damping device 10. The idle vibrations among the vibrationshave relatively small amplitudes but high frequencies, and the shakevibrations have low frequencies but great amplitudes. Therefore, whensuch normal vibrations are input, a flow velocity of the liquid Lflowing into the vortex chamber 31 via the first rectifying passages 32b can be increased to a predetermined value or more in any case, and aswirl flow of the liquid L can be formed in the vortex chamber 31 asindicated by an arrow in FIG. 3. The swirl flow in the vortex a her 31rotates in one direction in the vortex chamber circumferentialdirection.

As a result, pressure loss of the liquid L is increased due to, forexample, viscous resistance of the liquid L energy loss occurring whenthe swirl flow is formed, energy loss due to friction between the liquidL and wall surfaces of the vortex chamber 31, and so on, and thevibrations are thus absorbed and attenuated. At this time, the flow rateof the liquid L flowing into the vortex chamber 31 is significantlyincreased in accordance with an increase in a flow velocity of theliquid L so that the vortex chamber 31 is sufficiently filled with theswirl flow formed by the liquid L flowing into the vortex chamber 31.When the liquid L is caused to further flow into the vortex chamber 31in this state, the pressure loss of the liquid L can be more reliablyincreased.

After that the liquid L which is caused to rotate in the vortex chamber31 flows out of the second rectifying passages 33 b and flows into thesubsidiary liquid chamber 15 via the second communicating section 33.The second rectifying passages 33 b extend outward in the vortex chamberradial direction in common with the first rectifying passages 32 b andextend in one direction in the vortex chamber circumferential direction.Because of this, a direction in which the liquid L rotates in the vortexchamber 31 in the vortex chamber circumferential direction and adirection in which the second rectifying passages 33 b extend in thevortex chamber circumferential direction can be commonly set to be theone direction in the vortex chamber circumferential direction. Thus, itis difficult for the liquid L which rotates in the vortex chamber 31 toflow into the second rectifying passages 33 b, and thus the liquid L canefficiently rotate in the vortex chamber 31. In other words, asufficient distance to move the liquid L can be secured, and thepressure loss of the liquid L can thus be more reliably increased.

Also, when the liquid L in the subsidiary liquid chamber 15 is caused toflow toward the main liquid chamber 14 via the vortex chamber units 30,the liquid L flows into the vortex chamber 31 via the second relaychamber 33 a and the second rectifying passages 33 b. Even at this time,when the flow velocity of the liquid L is a predetermined value or more,the swirl flow of the liquid L can be formed in the vortex chamber 31 asindicated by the arrow in FIG. 3. Thus, the pressure loss of the liquidL is increased, and the vibrations are absorbed and attenuated.Incidentally, the swirl flow in the vortex chamber 31 rotates in the onedirection in the vortex chamber circumferential direction similarly tothe swirl flow of the liquid L which has flowed from the firstrectifying passages 32 b.

After that, the liquid L which is caused to rotate inside the vortexchamber 31 flows out of the first rectifying passages 32 b and flowsinto the main liquid chamber 14 via the first communicating section 32.Here, the first rectifying passages 32 b extend outward in the vortexchamber radial direction in common with the second rectifying passages33 b and extend in the one direction in the vortex chambercircumferential direction. Thus, the direction in which the liquid Lrotates in the vortex chamber 31 in the vortex chamber circumferentialdire-lion and a direction in which the first rectifying passages 32 bextend in the vortex chamber circumferential direction can be commonlyset to be the one direction in the vortex chamber circumferentialdirection. Thus, it is difficult for the liquid L which rotates in thevortex chamber 31 to flow into the first rectifying passages 32 b, andthus the liquid L can efficiently rotate in the vortex chamber 31. Inother words, a sufficient distance to move the liquid L can be secured,and the pressure loss of the liquid L can thus be more reliablyincreased.

Further, minute vibrations, for example, higher in frequency andremarkably smaller in amplitude than an assumed value, areunintentionally input to the vibration-damping device 10 in some cases.When the minute vibrations are input, the flow velocity of the liquid Lflowing into the vortex chamber 31 via the first rectifying passages 32b and the second rectifying passages 33 b is low. Thus, the rotation ofthe liquid L in the vortex chamber 31 is suppressed. When the swirl flowof the liquid L is not generated in the vortex chamber 31, the liquid Lsmoothly flows through the vortex chamber 31. Thus, an increase in adynamic spring constant is suppressed.

As described above, according to the vibration-damping device 10 relatedto this embodiment, the swirl flow of the liquid L is formed in thevortex chamber 31 so that the pressure loss of the liquid L isincreased, and the vibrations can thus be absorbed and attenuated. Whennormal vibrations such as, for example, idle vibrations and shakevibrations are input, the vibrations can be absorbed and attenuated inaccordance with the flow velocity of the liquid L irrespective of thefrequencies of the vibrations. Also, the first rectifying passages 32 band the second rectifying passages 33 b are open at the innercircumferential surface of the vortex chamber 31 which faces the outsidein the vortex chamber radial direction (the outer circumferentialsurface of the core part 39 d which forms the vortex chamber 31 in thevortex chamber circumferential direction. Thus, the size of the swirlflow is secured by increasing the outer diameter of the vortex chamber31, and the pressure loss of the liquid L can thus be reliablyincreased. Also, the first rectifying passages 32 b and the secondrectifying passages 33 b are disposed inside in the vortex chamberradial direction. Thus, the compactness of the vibration-damping device10 can be realized. Therefore, simplification of a structure andfacilitation of manufacture can be achieved while a plurality of kindsof vibrations having different frequencies are absorbed and attenuated.

Also, an increase in a dynamic spring constant can be suppressed in astate in which the flow velocity is low and the rotation of the liquid Lin the vortex chamber 31 is suppressed. When the flow velocity of theliquid L is lower than that when normal vibrations are input, such aswhen unintentional vibrations such as, for example, minute vibrationshigher in frequency and remarkably smaller in amplitude than the normalvibrations are input, an increase in the dynamic spring constant can besuppressed. Thus, product features of the vibration-damping device 10can be easily secured.

Also, the first rectifying passages 32 b are included in the firstcommunicating section 32, and the second rectifying passages 33 b areincluded in the second communicating section 33. Thus, the liquid Lflowing from the main liquid chamber 14 to the subsidiary liquid chamber15 is caused to flow into the vortex chamber 31 via the first rectifyingpassages 32 b so that the pressure loss of the liquid L can beincreased. In addition, the liquid L flowing from the subsidiary liquidchamber 15 to the main liquid chamber 14 is also caused to flow into thevortex chamber 31 via the second rectifying passages 33 b so that thepressure loss of the liquid L can be increased. Thus, the vibrations canbe effectively absorbed and attenuated.

Also, the first rectifying passages 32 b and the second rectifyingpassages 33 b extend outward in the vortex chamber radial direction fromthe inner circumferential surfaces of the first relay chamber 32 a andthe second relay chamber 33 a and open at the inner circumferentialsurface of the vortex chamber 31. Thus, the liquid L flowing from themain liquid chamber 14 to the first relay chamber 32 a in the axial Odirection can be caused to flow via the first rectifying passages 32 bin the vortex chamber radial direction and then flow into the vortexchamber 31 from the inner circumferential surface of the vortex chamber31 in the vortex chamber circumferential direction. Also, the liquid Lflowing from the subsidiary liquid chamber 15 to the second relaychamber 33 a in the axial O direction can be caused to flow via thesecond rectifying passages 33 b in the vortex chamber radial directionand then flow into the vortex chamber 31 from the inner circumferentialsurface of the vortex chamber 31 in the vortex chamber circumferentialdirection. Thus, the liquid L flowing from the first rectifying passages32 b and the second rectifying passages 33 b to the vortex chamber 31can be easily and accurately caused to rotate in accordance with theflow velocity thereof.

Note that the technical scope of the present invention is not limited tothis embodiment and can be modified in various ways without departingfrom the spirit of the present invention.

In the present invention, constitutions of the first rectifying passages32 b and the second rectifying passages 33 b are not limited to thoseshown in this embodiment.

For example, as shown in FIGS. 5 and 6, in the planar view, a firstrectifying passage 32 b and a second rectifying passage 33 b may beformed in the same width the entire length from the inside to theoutside in the vortex chamber radial direction. Incidentally, the firstrectifying passage 32 b and the second rectifying passage 33 b extend intangential directions of the inner circumferential surfaces from theinner circumferential surfaces of a first relay chamber 32 a and asecond relay chamber 33 a (the inner circumferential surface of a corepart 39 d which forms the first relay chamber 32 a and the second relaychamber 33 a).

Also, as shown in FIGS. 5 and 6, one first rectifying passage 32 b andone second rectifying passage 33 b may be provided, or a plurality offirst rectifying passages 32 b and a plurality of second rectifyingpassages 33 b may be provided.

Also, in this embodiment, the first rectifying passage 32 b and thesecond rectifying passage 33 b extend outward in a liquid chamber radialdirection and gradually extend in common in the one direction in thevortex chamber circumferential direction, but the present invention isnot limited thereto. For example, the first rectifying passage and thesecond rectifying passage may extend outward in the liquid chamberradial direction and extend in different directions around a liquidchamber axis.

In this embodiment, the first communicating section 32 and the secondcommunicating section 33 are provided with relay chambers 32 a and 33 a,respectively, but the present invention is not limited thereto. Forexample, the rectifying passages may be directly joined to the mainliquid chamber or the subsidiary liquid chamber without the relaychambers.

Also, in this embodiment, the rectifying passages (the first rectifyingpassage 32 b and the second rectifying passage 33 b) are included inboth of the first communicating section 32 and the second communicatingsection 33, but the present invention is not limited thereto. Forexample, the rectifying passages may be appropriately changed to anotherform in which the rectifying passages are provided in at least one ofthe first communicating section and the second communicating section.

The vortex chamber 31 is not limited to the chamber shown in thisembodiment and may be appropriately changed to another annularconstitution in which the vortex chamber 31 rotates a liquid flowinginto an inside thereof from the rectifying passages in accordance with aflow velocity thereof.

In this embodiment, the main liquid chamber 14 and the subsidiary liquidchamber 15 communicate with each other only via the vortex chamber unit30, but the present invention is not limited thereto. For example anorifice which passes through the main liquid chamber and the subsidiaryliquid chamber may be provided in the partition member independentlyfrom the vortex chamber unit. A constitution in which resonance (liquidcolumn resonance) occurs when a liquid flows in the orifice can beadopted as the orifice.

In this embodiment, the partition member 16 partitions the liquidchamber in t first attachment member 11 into the main quid chamber 14having the elastic body 13 as a portion of the wall surface thereof andthe subsidiary liquid chamber 15, but the present invention is notlimited thereto. For example, a pair of elastic bodies may be providedin the axis direction without providing the diaphragm, and a pressurereceiving liquid chamber having an elastic body as a portion of a wallsurface thereof may be provided without providing the subsidiary liquidchamber. In other words, the constitution of the present invention maybe appropriately changed to another constitution in which the partitionmember partitions the liquid chamber in the first attachment member inwhich the liquid is sealed into the main liquid chamber and thesubsidiary liquid chamber, and at least one of the main liquid chamberand the subsidiary liquid chamber has an elastic body as a portion ofthe wall surface thereof.

In this embodiment, the case in which the engine is joined to the secondattachment member 12, and the first attachment member 11 is joined tothe vehicle body has been described, but the vehicle body may be joinedto the second attachment member 12, and the first attachment member 11may be joined to the engine.

The vibration-damping device 10 related to the present invention is notlimited to an engine mount of the vehicle and can also be applied tocomponents other than the engine mount. For example, thevibration-damping device 10 can also be applied to mounts of electricgenerators mounted on construction machines or can also be applied tomounts of machines installed at factories or the like.

In addition, the constituent elements of the above-described embodimentscan be appropriately replaced with well-known constituent elementswithout departing from the gist of the present invention, andappropriately combined with the modified examples described above.

INDUSTRIAL APPLICABILITY

According to the present invention, simplification of a structure andfacilitation of manufacture can be achieved while product features aresecured.

REFERENCE SIGNS LIST

-   -   10 Vibration-damping device    -   11 First attachment member    -   12 Second attachment member    -   13 Elastic body    -   14 Main liquid chamber (first liquid chamber)    -   15 Subsidiary liquid chamber (second liquid chamber)    -   16 Partition member    -   30 Vortex chamber unit    -   31 Vortex chamber    -   32 First communicating section    -   32 a First relay chamber    -   32 b First rectifying passage    -   33 Second communicating section    -   33 a Second relay chamber    -   33 b Second rectifying passage    -   L Liquid

The invention claimed is:
 1. A vibration-damping device in which atleast one of a first liquid chamber and a second liquid chamber has anelastic body as a portion of a wall surface thereof, thevibration-damping device comprising: a tubular first attachment memberjoined to one of a vibration generating unit and a vibration receivingunit; a second attachment member joined to the other of the vibrationgenerating unit and the vibration receiving unit; the elastic body whichjoins the first attachment member to the second attachment member; and apartition member which partitions a liquid chamber in the firstattachment member in which a liquid is sealed into the first liquidchamber and the second liquid chamber, wherein the partition member isformed with a vortex chamber unit through which the first liquid chambercommunicates with the second liquid chamber, the vortex chamber unit isprovided with an annular vortex chamber, a first communicating sectionthrough which the vortex chamber communicates with the first liquidchamber, and a second communicating section through which the vortexchamber communicates with the second liquid chamber, and at least one ofthe first communicating section and the second communicating sectionincludes a rectifying passage which extends outward in a radialdirection from a portion of the partition member which is more inward ina radial direction of the vortex chamber than the vortex chamber and areopen at an inner circumferential surface of the vortex chamber whichfaces the outside in the radial direction in a circumferential directionof the vortex chamber, the vortex chamber includes an annular gap whichextends throughout an entire circumference in the circumferentialdirection of the vortex chamber, and the vortex chamber is formed torotate a liquid flowing into the vortex chamber from the rectifyingpassage in accordance with a flow velocity thereof.
 2. Thevibration-damping device according to claim 1, wherein the rectifyingpassage is included in both of the first communicating section and thesecond communicating section.
 3. The vibration-damping device accordingto claim 2, wherein a first rectifying passage included in the firstcommunicating section as the rectifying passage and a second rectifyingpassage included in the second communicating section as the rectifyingpassage extend outward in the radial direction and gradually extend incommon in one direction in the circumferential direction.
 4. Thevibration-damping device according to claim 1, wherein a communicatingsection of the first communicating section and the second communicatingsection which is included in the rectifying passage is provided with arelay chamber of the partition member which is more inward in the radialdirection than the vortex chamber, the relay chamber is configured tocommunicate with the first liquid chamber or the second liquid chambervia an opening which is open in an axial direction of the vortexchamber, and the rectifying passage extends outward in the radialdirection from an inner circumferential surface of the relay chamberwhich faces the inside in the radial direction and is open at the innercircumferential surface of the vortex chamber.